Traffic calming devices such as speed bumps operate on the principle that an obstruction placed in the way of a vehicle will encourage drivers to slow down to avoid the unpleasant sensation of passing over the obstacle at speed, and the corresponding damage that this may cause to their vehicles.
However, speed bumps suffer from the disadvantage that the potential damage done to a vehicle will depend on the configuration of that vehicle. For example, sports cars which have a low clearance height might suffer damage not only to the suspension, but also to the body of the vehicle if the clearance height is not sufficient. In contradistinction, sport utility vehicles have high clearance heights and suspension designed to accommodate obstacles. Therefore, drivers of such vehicles have little or no incentive to slow down in the knowledge that the potential damage to their vehicles will be minimal.
Dynamic speed bumps which are raised and lowered on demand are known. However, these dynamic speed bumps operate by being attached to a speed sensor which determines the speed of the approaching vehicle and lowers the speed bump if the speed is less than the speed limit.
Such dynamic speed bumps suffer from the disadvantage that they are costly to produce and maintain, and require significant energy requirements to operate.